According to Auto Laundry News surveys, over one-half of respondents operate an in-bay automatic on their coin-operated location.

            This is a long-running trend. It is not uncommon to come across a site with several spray bays and one or two in-bay automatics. Operators sometimes convert a spray bay into an in-bay to take advantage of the market trend.

            Similarly, some operators will convert an in-bay automatic into a mini-tunnel to exploit the same trend. Regardless of the business case, the decision to retool a business model is huge.

            First, a potential wash must comply with zoning regulations, building codes, environmental regulations, and current applicable ordinances. If the government legally permits the project, it must be physically possible. A conversion project may be limited by physical characteristics such as the size and shape of the parcel of land, frontage, available utilities, or some other condition.

            There must be sufficient space for vehicle stacking, turning movements, navigation across the site, and parking. How much space is needed will depend on the anticipated increase in sales volumes.

            To illustrate, shown in Table 1 is a waiting line model for a single in-bay based on a service rate of 12 customers per hour. The model shows that at low customer arrival rates, the probability of someone having to wait in a short line is about a coin toss.

            However, once the arrival rate reaches and exceeds 75 percent of hourly capacity, the length of the waiting and probability of waiting increases exponentially. Generally speaking, this is often the tipping point when customers are most likely to line defect or balk at entering the queue.

            The only way to overcome this situation is to increase the service rate of the machine or add another machine.

            Table 2 contains a waiting line model for two in-bay units, each with a service rate of 12 customers per hour. The model shows the tipping point is pushed out to an arrival rate of 18 customers an hour and the probability of waiting is lower.

            This suggests a sweet spot for two in-bays of 30,000 cars per year. This would leave room, so to speak, for the additional volume generated by a loyalty program.

            Table 3 contains the waiting line model for a mini-tunnel often described as having a service rate three times greater than in-bay (36 cars an hour). The model shows at the dual in-bay’s tipping point or arrival rate of 18 customers an hour, there is only a 50 percent probability of waiting at a mini-tunnel.

            It’s not until the arrival rate reaches and exceeds 75 percent of hourly capacity that the length of the waiting and probability of waiting increases significantly.

            Regardless of choice, a successful expansion and loyalty program will create times when demand exceeds capacity, resulting in long average waiting times. After all, adding a second in-bay provides a step-wise increase in capacity and a 38’ or 45’ conveyor isn’t very long.

            If the project is physically possible, it must be financially feasible. Feasibility implies the use can generate sufficient income and cash flow to sustain the project, meet all debt obligations, and produce some net return to the property.

            Finally, if the project is financially feasible, it must be maximally productive. This requires the evaluation of the value created by the use and the costs to achieve this value to determine which use provides the maximum return.

            Determining feasibility and maximum return will require market analysis, sales projections, and estimated control budgets for each use. Control budgets should be prepared using the same categories to make an apples-to-apples comparison. For example, site work, POS/software, car wash equipment, support equipment, installation, building renovations, soft cost, and contingencies.

            The same applies to financial analysis. For example, there is not much difference in energy and water consumption between a five-brush in-bay and a five-brush 38’ or 54’ conveyor, whereas touch-less in-bay does use more.

            Other factors that must be considered are price, sales mix, and operating expenses. For example, in-bay does not require attendants to operate 24/7/365. Semi-absentee ownership is possible with time allowed for housekeeping, maintenance, and administration.

            If the plan is to clean 300 cars on a busy day with a 38’ or 45’ conveyor, expect many hours during that day to be above 30 cars with several cars or more waiting in line.

            Moreover, conveyors typically open at 7 or 8 a.m. and close at 7 or 8 p.m. Consequently, with a monthly plan and amenities such as free vacuums and a towel program, the mini-tunnel should budget 100 hours of labor per week.

Bob Roman is a car wash consultant and can be reached at